classiccarsfandomcom-20200223-history
Triumph TR7 Sprint
The Triumph TR7 Sprint was a development of the Triumph TR7 sports car, manufactured by the Triumph Motor Company (part of British Leyland) during 1977. The main development from the TR7 was the replacement of the 105 bhp 2-litre, 8-valve version of the Triumph Slant-4 engine with the 2 litre 16 valve version, which was already in use in the Dolomite Sprint, and in that guise produced 127 bhp; however, "reliable sources claimed that well built and tuned engines, with stock components, had been known to give a sustained 150 bhp on the factory test bed". The TR7 Sprint was apparently ready for full production when there was a major strike at the BL Speke plant in 1977-8. Following this, the plant was closed, production of the TR7 was moved to Canley, Coventry, and the TR7 Sprint was cancelled. However, a small number of prototype and pre-production TR7 Sprints, both left and right hand drive, were manufactured between February and October 1977, in fixed head coupé form only. The exact number produced is a subject of speculation, and it appears that "surviving records are incomplete." However there are build records in the archives of the British Motor Industry Heritage Trust (BMIHT) – based at the Heritage Motor Centre in Gaydon, near Warwick - for 59 cars, and at least one other, for which there is no BMIHT build record, is known to exist. Performance Data *0 - 60: 8.5 seconds (estimated) *Max speed: 120 mph (estimated) The (estimated) top speed and 0-60 times of the TR7 Sprint are almost identical to those for the US specification carburettor version of the 3.5 litre 135 bhp Rover V8 powered Triumph TR8, which are 120 mph and 8.4 seconds. One of the then Triumph engine development engineers is quoted as saying "The real test was the 30-50, 50-70mph times and here the Sprint was significantly superior to the 2V engine and even challenged the TR8's abilities. Certainly, if we were going 'off site' the preferred vehicle to 'borrow' was a Sprint TR7 over all others and that includes the TR8." The 150 hp power output given for "well built" Sprint engines must be very close to the 153 PS DIN (±5%) that was given by the Rover V8 engine in the UK Specification TR8. Hence, it is possible that had Triumph produced the TR7 Sprint and TR8 to UK specification, as was apparently planned at one time, there would have been significant debate of their relative merits, some of it probably rather partisan in nature. Distinguishing features "There are a (comparatively) large number of privately built Sprint conversions about... Buyers should beware of this if they are asked a premium price for an alleged 'genuine' TR7 Sprint":all the essential parts to turn a TR7 into a functional copy of a TR7 Sprint, though not an identical one, can either be sourced from a Dolomite Sprint or remain available from suppliers; several companies sell conversion kits online; and several sources provide information and advice on this TR7 Sprint conversion,as well as a number websites. According to one of these sources, "this upgrade brings you into the same power band as an original TR8, but for a fraction of the cost, effort and time." The factory TR7 Sprints have chassis numbers that are prefixed with letters ACH; whereas, UK/Australian/European specification TR7s of the time were prefixed ACG: Figure 5 shows a chassis or commissioning plate from a TR7 Sprint car, mounted on the left hand door, below the door lock. The TR7 Sprint engines are also prefixed with CH, rather than GC on the TR7's and VA on Dolomite Sprint engines; however, the TR7 Sprint engine numbers can, at least in some cases, be very hard to read (see Figure 6). It seems that there is no disagreement that "All (factory TR7 Sprint) cars were fixed-head coupes", that the period over which they were built spans the changeover between the 1977 and 1978 year model bodies,and both right and left hand drive cars were produced. There are a number of parts specific to the TR7 Sprint, i.e. not used on the TR7, TR8, or Dolomite Sprint; however, there are alternative parts or alternative methods for all of these: the cast steel exhaust manifold, and the front pipe of the exhaust system (which has been remanufactured, RB7385); a water transfer plate, at the back of the cylinder head (also remanufactured, RB7240); there are at least two different Engine information panels (UKC 8605 and TKC 5228), on the underside of the bonnet, some of which only indicate TR7, but provide slightly different information to that on the equivalent TR7 part (UKC 6246); the front disks, although the callipers and dust shields, etc., were as those used on the TR8 so TR8 disks fit. There are online photographs of some of these parts. A number of parts in the throttle linkage are also unique to the sprint, most obviously the link plate between the two carburettors (just visible in Figure 3, and partially obscuring the inlet manifold in Figure 4), which is not fitted to the Dolomite; and the throttle lever/link rod (visible just over the air box in Figure 4), which looks the same as the TR7 part, but is longer to allow for the carbs being further apart. Internally, within the cabin, at least some of the cars were fitted with the large semi-circular pad on the steering wheel from the US specification TR7 (RKC82) (see Figure 7). Some of the TR7 Sprints carried side stripes with the word "Sprint" on the rear wings. These are shown in a photograph of what appears to be a US Spec., 1977 y.m. car; the caption to which states "The sides of the TR7 Sprint were supposed to have received this striping treatment, designed by John Ashford, had the car gone into production." These stripes are also shown in contemporary pictures of an original, but unidentified, TR7 Sprint from the press garage, which are available from the BMIHT. The TR7 Sprint shown in figures 1 to 4 is, in this respect, identical with these photographs, except for the colours. The stripes themselves were reworked for the TR7 Premium edition after the TR7 Sprint was still born. They were, at one time, listed by Moss Europe (previously TriumphTune) under BL part numbers YKC2082-2087. There are also photographs of TR7 Sprints bearing small 'SPRINT' decals on the front panel and boot lid below the 'TR7' decal that was standard fit on Speke built TR7s. This uses the same font as this TR7 decal and in the stripes used on the TR7 Premium edition. There is also a, presumably contemporary, photograph of one of these decals on a V8 powered car.However, it is reported that a number of different decal sets were being tried out on these pre-production cars. There is also a description of a car with the triumph TR7 decal on the left side of the boot lid, and a large Sprint decal on the right These sprint decals were also at one time available from Moss Europe (in three sizes), though they do not seem to have been catalogue items nor are they identified by BL part numbers. One size is still available as supplier part No. RB7206BLACK/SILVER/GOLD. However, it appears that there are no photos or descriptions of the Sprint decals on the front or rear of an original, unrestored TR7 Sprint that is identified as being home market specification; neither are these decals identified to BL part numbers. Whereas, the BMIHT photos of the press garage car should be definitive of this specification, and the side stripes are identified by their designer and their BL part numbers. Hence it may be speculated that the small Sprint decals were early designs that were tried out on the prototypes, but the Sprint side stripes represented the intended final version; albeit, tried out and photographed out on at least one prototype. Cancelation The main reasons given for the cancelation relate, ultimately, to the "replacement of the aristocratic Lord Stokes with South African businessman Michael Edwardes" as managing director in 1977, which, it seems, lead almost immediately to a 17 week long strike at Speke, where the TR7 and the few TR7 Sprints were manufactured. This resulted in the closure of the plant in May 1978, and the move of production to Canley, Coventry and led to the cancelation of the TR7 Sprint. Another reason given is that the BL marketing department caused the cancellation, because the 0 - 60 time and top speed was not sufficiently different from the TR7's. However, it is also the case that, unlike the TR7 and TR8, the Sprint's 16 valve engine was not suitable for the emissions control equipment needed for the US market, which was the main target market for the TR7 and 8. Development of the 16 valve version of the slant four engine that would have addressed this emission control issue had been underway for the Triumph SD2 - BL Specialist Division’s project, after the Rover SD1 -, which was, apparently, intended to replace the dolomite range. However, the SD2 had been cancelled in 1975, and the Dolomite was replaced in 1981 by the Triumph Acclaim, based on the Honda Ballade and with a Honda designed engine. When the TR7 Sprint programme was cancelled, and the cars became redundant, "most were sold off to private buyers" and some went into BL's management car plan and were leased to BL employees. Publications The BL TR7 Repair Operations Manual, AKM3079A, covers both the 4 and 2 valve (per cylinder) engines; however, an erratum stuck to the title page states "At the time of going to press the 4 valve engine referred to in this manual has not been fitted to the Triumph TR7" An owner's handbook, AKM 3967, was also produced for TR7 Sprint in 1977, but is apparently for the 1977 year model: it shows the interior light in the headlining not the doors. It also lists only the 5 speed (LT77) gearbox, unlike the similar handbook for the TR7, RTC 9210, which lists the 4 speed and the 5 speed as an option. However, some of the information contained in this TR7 Sprint handbook is incorrect for the TR7 Sprint, i.e. pictures show the 8 valve engine and the TR7's AC Delco distributor. Use in competition The TR7s used by BL in rallying, from their advent in the Welsh rally of 1976 until the coming of the Rover V8 3.5 litre TR7V8 rally cars in 1979 used the 16 valve 2 litre Sprint engines and were, in effect, TR7 Sprints. These rally cars proved competitive on asphalt, winning a number of events including the Belgian Boucles de Spa rally in 1977. Four of the later BL works rally cars bear the registrations of cars from the press garage, SJW 533S, SJW 540S, SJW 546S, and SJW 548S. SJW 533S was initially campaigned as a 4 cylinder 16 valve car, and later as a V8 3.5 Litre TR7V8 specification. The other three were only ever campaigned as TR7V8s. However, it is not clear whether or not the four rally cars bearing these registrations actually were the TR7 Sprints from the press garage, or whether only the registrations were used. There is a story at one TR7 related website that Motorsport director, John Davenport, "needed white cars without sunrooves and these were the nearest four." However, according to the press garage data (Figure 8), SJW 533S was russet, SJW 540S was java green, SJW 546S was brooklands green, and SJW 548S was carmine; though none had sun-roofs. While there are suggestions that the cars sent to the press garage were re-trimmed and even possibly re-sprayed, there are no suggestions that their paint colours were changed, and the competitions department could, presumably, have managed that themselves, were it significant. Equally anecdotally, a more complete reproduction of the 1991 owner written article from the TR Driver's Club magazine states "Although the SJW TR7V8 rally cars began life as TR7 Sprints, the rally cars were scratch built using bodies taken off the line and prepared by Safety Devices. So only the registration numbers from the sprints were used." Category:Triumph Category:Post-war Category:Racecars